Fabrication of La1-XSrxCoO3–Sc2O3–ZrO2 Composite Cathode By Electrochemically Assisted Deposition for Solid Oxide Fuel Cells

Abstract

We developed a novel method for the fabrication of La1-xSrxCoO3–Sc2O3–ZrO2 (LSC–SSZ) composite cathode for solid oxide fuel cells (SOFC) via electrochemically assisted deposition of La1-xSrxCoO3 (LSC) into a porous Sc2O3–ZrO2 (SSZ) scaffold. To do so, a highly porous SSZ scaffold was fabricated by screen printing an SSZ ink containing 30 wt % PMMA pore-former onto a dense SSZ electrolyte layer of a NiO–SSZ|SSZ half-cell. The porous SSZ scaffold was made electrically conductive for the electrodeposition process by carbon deposition in a flowing N2/ethylene environment at 800 °C. Subsequently, lanthanum, strontium and cobalt were simultaneously deposited into the porous carbon coated SSZ scaffold by electrochemically assisted deposition involving nitrate reduction and hydroxide precipitation processes. To form an LSC perovskite phase, the button cells were heat treated in air at 800 °C for 5 h. The LSC–SSZ composite cathode functional layer was characterized by the SEM, EDS and XRD analysis. The results indicated a formation of LSC into the porous SSZ scaffold in the form of dendrites initially and as the deposition time was increased the LSC dendrites were thickened and finally formed a dense layer on the top of SSZ scaffold. The deposition was found to be uniform inside the SSZ scaffold up till the cathode/electrolyte interface. The electrochemical testing of button cells showed a high performance, which indicated that the developed technique is promising and it should be further explored to fabricate high performance SOFCs.